This invention relates to readied in situ glyphosate herbicide soluble powder compositions of high efficiency and low toxicity useful for killing and/or controlling weeds. This invention is also related to a process to prepare the said compositions. It is another object of this invention to provide new compositions that consist of a soluble powder herbicide formulation characterized by a very narrow range of specific ingredients of composition, which optimize the formulation efficiency and minimizes the cost and toxicity to man, to the environment and to the crop being treated. The required amount of glyphosate that needs to be applied on the field is reduced by 30% when compared to the commercially standard liquid solution.